Brain-computer interface (BCI) technology involves the acquisition and interpretation of brain signals to determine the intentions of the person that produced the brain signals, and then using the determined intentions to carry out intended tasks. One example application of BCI technologies is the control of a cursor on a computer screen. There are many others.
Another example application area for BCI technologies is in connection with stroke patients. Unilateral stroke, for example, is a stroke event that affects only, or mainly, one side of the brain. When a unilateral stroke occurs, the opposite side of the stoke victim's body may be left paralyzed or weak. That is because in normal function, one side or hemisphere of the brain controls the opposite, or contralateral, side of the body. Thus, the right brain, or right cerebral hemisphere, controls the left side of the body, and vice-versa.
Patients who have experienced a brain injury (e.g., stroke, trauma, infection, hemorrhage, neonatal malformation, cerebral palsy, or neurodegenerative) typically undergo some type of rehabilitation in an attempt to restore or strengthen the motor impaired or paralyzed side of the body, often using a variety of rehabilitation devices that aid in the rehabilitation effort. Often, the rehabilitation method involves equipment that requires the patient, in order to perform the necessary rehabilitation activities, to be at a particular location such as a rehabilitation facility where the equipment is located. The present inventors believe that such constraints often negatively impact the potential for success in the rehabilitation effort for a variety of reasons. For example, use of rehabilitation equipment at a rehabilitation facility can cause the rehabilitation to be performed outside of the context of the patient's domestic needs (e.g., performing daily activities at the patient's home) and can cause the rehabilitation to be limited to specific amounts of time, both of which can limit progress made a patient during rehabilitation. Repetitions in the context of a patient's living environment with objects and surrounding from a patient's daily life can increase the effectiveness of rehabilitation activities. Rehabilitation using rehabilitation equipment that is removed from such a context (e.g., patient's home) and that is available for limited periods of time (e.g., scheduled appointments at rehabilitation facility) may not be optimized to provide the best recovery for a patient.
The use of BCI technology for stroke patient rehabilitation is described, for example, in U.S. patent application Ser. No. 12/133,919 to Leuthardt et al. ('919 application). The '919 application describes a BCI system to assist a hemiparetic subject, or in other words, a subject who has suffered a unilateral stroke brain insult and thus has an injury in, or mainly in, one hemisphere of the brain. For that patient, the other hemisphere of the brain may be normal. The '531 patent application describes an idea of ipsilateral control, in which brain signals from one side of the brain are used to control body functions on the same side of the body. The present inventors believe this idea of ipsilateral control is particularly useful in the context of unilateral stroke patients where, again, the opposite brain hemisphere may be damaged or impaired and thus may not produce useful brain signals for use by a BCI system.